Table 1.

Sequences and activities of the SDF-1α and SDF-1 β preparations

Preparation	Derivation	Syncytia blocking	IC90 μM	Biologic activity	N-terminal sequence	C-terminal sequence
SDF1-α 1–67	Synthetic	+	≤0.12	+*	KPVSLSYR	ALN
SDF1-α 6–67	Synthetic	ND	ND	−†	SYR	ALN
SDF1-α 1–68	Recombinant	+	≤0.13	+‡	KPVSLSYR	ALNK
SDF1-α −2 to 68	Synthetic	−	≥1.6	+§	DGKPVSLSYR	ALNK
SDF1-β 1–72	Recombinant	+	≤0.11	+‡	KPVSLSYR	ALNKKRFM
SDF1-β −3 to 72	Recombinant	−	≥1.0	+¶	SDGKPVSLSYR	ALNKKRFM

The sources of the preparations are given in Materials and Methods. 

^*Measured by chemotaxis of human lymphocytes; maximal at ≈125 nm (26). 

^†Measured by chemotaxis of human lymphocytes; inactive up to ≈1 μM (26). 

^‡Measured by microphysiometer in Jurkat T cells EC50 ≈100 nM (R.H and M. Liang unpublished data). 

^§Measured by chemotaxis in human hNT neurons EC50 ≈50 nM (33). 

^¶Measured by chemotaxis of human T-lymphocytes in IL-2 for 8-10 days, ED₅₀ ≈ 60 nM (R & D Systems).